Numbers 18:11-13

And this is thine: the heave-offering of their gift, even all the wave-offerings of the children of Israel; I have given them unto thee, and to thy sons and to thy daughters with thee, as a portion for ever; every one that is clean in thy house shall eat thereof. All the best of the oil, and all the best of the vintage, and of the grain, the first-fruits of them which they give unto Jehovah, to thee have I given them. The first-ripe fruits of all that is in their land, which they bring unto Jehovah, shall be thine; every one that is clean in thy house shall eat thereof.